Genetic testing and childhood obesity

It’s a sad reality: Childhood obesity is one of the most serious modern public health challenges we face. The global problem is steadily affecting many low- and middle-income households – particularly in urban settings. In 2010, it was estimated that 42 million children worldwide were suffering from obesity, with up to 35 million living in developing countries, and this number is climbing.

According to a study published in International Journal of Epidemiology in 2016, in South Africa the number of youngsters suffering from obesity doubled in six years while this took 13 years to happen in the US.

What research suggests

A high body mass index (BMI) and obesity in childhood are known to have a significant impact on both physical and psychological health. According to the researchers, there is a 70% chance of an overweight child remaining overweight as an adult. Obese children are also more likely to develop non-communicable diseases like diabetes and cardiovascular diseases at a younger age.

Childhood obesity has a complex set of causes, with both lifestyle and genetic factors playing a role. Since the impact of childhood obesity on our children’s future health can be severe, it’s important to watch for early warning signs and screen children so early intervention strategies can be implemented to help them grow into healthy adults.

What causes childhood obesity?

According to the 2016 study, South African childhood obesity may be attributable to a variety of factors, including growth in gross domestic product (GDP)‚ more disposable income‚ increased exposure to globalisation, and the establishment of large urban informal settlements. These have led to changes in dietary patterns that now include cheap energy-dense foods‚ people drinking more sugary drinks, and increased consumption of saturated fats and animal proteins.

A 2015 review study in Journal of Family Medicine and Primary Care looked at the causes and consequences of childhood obesity and identified factors like high intakes of sugars, portion control, lack of activity, too many snack foods, and an array of social, emotional, and psychological factors.

It was also noted in the study that although childhood obesity is widely accepted to be a result of an imbalance in energy intake and expenditure, the role of genetics can’t be overlooked, with some studies showing that BMI is up to 45% heritable. Nutrigenetics is the scientific study of the interaction of nutrition and genes − especially in the prevention or treatment of disease.

By looking at specific genes, experts can now identify tendencies in our genetic blueprint and through this, they’re able to design more targeted dietary and lifestyle interventions. As our genetics are the same from the day we are born to the day we die, it makes sense to check some things out early in life − especially when there is already cause for concern.

How valuable is genetic screening for childhood obesity?

According to Helen Gautschi, registered dietician at DNAlysis, one of South Africa’s leading genetic testing laboratories, there are a number of genetic variants that have been strongly related to increased obesity risk in children. By identifying these variants early, it may be possible to make valuable changes to help prevent obesity in susceptible children.

According to Helen, early genetic testing as a screening tool is a grey area since phenotype (the physical expression of the gene) may still be a good measure and other factors should still be considered, including diet and environment. She adds genetic testing in children also comes with a host of ethical questions so, if nutrigenetic tests are being considered, the information must be handled in a responsible manner by a healthcare professional who is comfortable with both the science of nutrigenetics and the management of childhood nutrition.

How is your child’s weight measured?

Having a strong family history of obesity may be a warning sign, but not all obese parents will have an obese child, and having a normal BMI doesn’t exclude your child from becoming obese. The best way to ensure your child’s growth is within the normal range is to use a growth chart.

When your baby is born, his weight and length are usually recorded on a chart and plotted on a curve. This curve provides the clues and it’s imperative you have your child measured regularly by a healthcare provider. You can do this every three months if you’re concerned.

Bear in mind that healthy children come in many shapes and sizes, and what is considered normal may vary. Most children will start to shift weight on the growth chart at around six months, when they might start to reflect their more inherent family build. Breastfed babies are generally fatter in the earlier months before leaning out later on in the year.

Weight gain should also be measured relative to head circumference and length to fully understand a child’s progress. In general, your baby should double her birth weight by six months, and triple by a year. This equates to about 180g per week in the first three months, 120g per week between three and six months, and 80g per week between six and 12 months.

After this, your baby’s weight is tracked on the same growth chart until he reaches three years of age. He’ll then have a new growth chart that will take him to 20 years. According to the Centers for Disease Control and Prevention, if your child falls in the 95th percentile for BMI on her growth chart, she is obese.

Preventing and managing obesity

Try these nine top tips for preventing and managing childhood obesity:

1. Set an example by eating healthy yourself: If your child sees you exercising and eating salads and vegetables, she is more likely to do the same.
2. Promote movement: We live quite a sedentary lifestyle, so make sure to include lots of daily, and weekly, activities for your child and get her involved in whichever sports she takes a liking to.
3. Offer healthy snacks: Always have healthy snacks on hand for school and home time to prevent children from asking for sugary treats when they’re hungry.
4. Know your macros: It’s important to know, and understand, the macronutrients – proteins, carbohydrates, and fats – and how they contribute to overall caloric intake, and how to distribute them throughout the day to ensure balanced energy. A registered dietician can help.
5. Avoid fat-shaming: While it’s imperative to highlight the value of healthy eating and exercise, shaming a young child for being overweight can cause more damage than it’s worth.
6. Practise portion caution: Learn what a reasonable and age-appropriate portion size is for your child, and offer the right amounts of foods at each meal and snack to prevent
7. Practise tough love: For some parents, a defiant and fussy eater can be a great challenge. The important thing is not to give in to every whim. Your child will eventually succumb and make healthier choices.
8. Consistency is key: It’s almost impossible to offer your child 100% clean and balanced meals every day. Allow for some treats and cheats, but keep the consistency of healthy eating high. Overeating can be compensated for by increasing physical activity or offering healthier choices to counteract it.
9. Ask for help: If you’re unsure about whether your child might be at risk, ask a professional who can help with physical and genetic screening advice or intervention methods to help your child on her wellness journey.